| The
Truth about SARS Infection
Severe Acute Respiratory Syndrome - Symptoms and
Survival
Mutant virus warning given in 1998: Latest update:
30 June 2003

SARS infection was a major risk to world health.
Only vigorous efforts by many governments prevented a wider
epidemic. The threat of new mutant viruses continues and SARS was
a wake-up call. If SARS had become firmly established in the very
poorest nations with few facilities
for
contact tracing,
diagnosis, treatment and isolation, there would have been a small
but significant risk that it would have gone on to spread like
the 1918-1919 flu
which rapidly infected 400 million people of which
30 million died. SARS may be less infectious than Spanish flu (uncertain)
but SARS has a higher death rate - at least 10%.
"If we don't take great
care, SARS could become established in the poorest nations
- places like Burundi, Nigera or Malawi - which have neither
the high-tech capability of Toronto nor the totalitarian muscle
of China to contain it. If that happens, the consequencies
for global control could be grave." Dr
Patrick Dixon - interview on CNN Europe 29 April 2003 -see more
- What follows is an expanded version of a briefing by Dr Patrick
Dixon at the SARS Summit organised by World Bank's Global
Development
Learning
Network - government leaders from Vietnam, China, Mongolia, Phillipines,
Hong Kong and other nations.
- By the end of June 2003, 8,450 were already known
to be infected with the SARS
virus
in 28
countries,
of
which
at
least
810 had
died. New cases had fallen to zero, with outbreaks controlled
in most of China as well as Taiwan,
while the situation appeared to be resolved
in Hong Kong
and singapore, as well as Toronto.
Other
nations that had been affected included India, Brazil, Spain,
France, German, Italy, Republic of Ireland, Romania, Switzerland,
Thailand, United Kingdom, United States, Viet Nam.
- We have been in an urgent race against time to prevent the
risk of a future global SARS pandemic, with numbers of
cases in some places doubling in the past every 2 -3 weeks of
a disease with 10%
mortality
- up
to 50%
in those over 65. While most people with SARS infection do not
pass the SARS virus to others, a small minority (superspreaders)
seemed to be highly infectious, and the source of most new transmission.
The greatest risk from superspreaders was to the poorest nations
who would not have been able to mount either a high-tech
Western Toronto-style response,
nor
an authoritarian,
large-scale, highly organised kind of response such as the
one we eventually saw in China. A single superspreader
travelling in a place like Bujumbura or Lagos could have inadvertently
set in
motion
a
health crisis, reaching far beyond those cities.
- It appears that huge efforts to contain SARS have paid off,
and there is now a good chance that we will be able to totally
eliminate SARS,
but
a
risk
remains that we
may not. That remains the concern of the World Health
Organisation and
also
of the
Chinese government as well as leading virologists around
the world and is the reason why such active steps continue to
be taken to stamp out SARS
infection
now.
- The situation today is radically different from just a few
weeks ago, when the Chinese were
still very secretive,
unable
therefore to mobilise the population,
and denying
more
than 37
cases
in
Beijing. Now the official attitude is totally different, with
over 2,300 reported cases in the capital city, and vigorous national
responses at every level. If the Chinese had continued the official
silence and delay for another couple of weeks we would have faced
a far more serious challenge. However, we need to recognise that
the huge turnaround in China has only been
achieved
at enormous
social cost, with severe draconian measures, restriction of personal
liberties and other steps that would have been very difficult
for a Western nation to take.
- If things had continued as they were, with
a
mixture of denial, confusion, delay, ignorance,
bad decisions, poor data gathering, official decision-making
paralysis, incompetence, concealment, secrecy and government
apathy, then a pandemic would have
become far more likely.
- We have probably been helped by the advent of Summer when coronavirus
infections tend to become less of a problem for reasons we don't
fully understand. It may be that SARS will reactivate in a more
significant way in the Autumn / Winter months.
- We have seen that a single missed case can close an entire
hospital, spark a new epidemic, fill intensive care units and
place 7,000 into quarantine. While
places
like Toronto have contained local outbreaks, backed
by the best facilites in the world, we cannot expect that all
the
poorest parts of the world will be able to cope in the same way
with SARS-like outbreaks in future. More than 3 billion people
live on less than $2 a day, served by limited health care which
may
be
many
hours
walk
away.
These
communities are acutely vulnerable to the arrival of SARS or
similar viruses and to the impact of a significant cluster of
cases.
- Respiratory illnesses have the tendency to spread widely.
Flu kills 22,000 in the US every year, 400,000
worldwide, but SARS
is a far greater potential threat, because of its higher mortality
rate even though in most cases it is not as highly infectious
as in superspreaders.
- SARS infection is untreatable, hard to control, still poorly
understood, appears to spread in a similar way to the common
cold and kills
young as well as old. Although the vast majority of infections
appeared to be occurring after close contact with SARS patients
who are unwell, we know that the virus may remain
infectious
on contaminated
surfaces for up
to 24
hours.
That
means for example that plane travellers could in theory become
infected by SARS from an unknown person who disembarked the previous
day
- just
by
touching a meal tray or a light switch.
- Health care workers in China, Hong Kong and other nations have
made huge personal sacrifices to save lives, in ways that remind
us
of
the magnificent
efforts
of firefighters
on September 11. Nurses and
doctors
in hard-hit hospitals have found themselves on the
front
line
of
a battle
for survival,
in acts of great courage
and
heroism, in quarantine, shut up in their hospitals, forbidden
to see their families,
some
for
more
than
40 days, working day and night to care for those with SARS,
seeing
significant
numbers
of their
fellow workers become ill or die. They
have gone on day after day knowing that their own lives could
be at
risk
through
intimate
contact with severely ill people on the edge of life and death.
(See below for impact on hospitals).
- SARS became a potential issue of national security in some
parts of China as well as a major health threat and business
challenge.
- Because there is no treatment for SARS infection apart
from supportive measures, some of those who develop symptoms
had low incentives to report
themselves to the authorities, especially in developing countries
when local facilities are poor, and when they feared possible
victimisation, isolation,
loss of
personal freedom, forcible
removal from their families, becoming very ill and dying in the
wrong part of the world, and so on.
- Even if we do eliminate SARS, we remain at risk of future
viral mutations, and should expect more dangerous new viruses
to emerge over the next ten years. We have seen many such mutations
over the last three decades including HIV and HK5.
- If SARS had spread
widely, it could have profoundly damaged confidence in the
global economy,
reducing growth by more than 1% world-wide, and of hard-hit
nations by more than 2%.
- The
influenza pandemic of 1918-1919 is a reminder to us of how
dangerous new viruses can be. It
killed more people than the Great War, (known
today as the first world war or WW1).
Estimates vary but some believe as many as half a billion people
were infected of which 30 million died. It was the most devastating
epidemic in recorded world history. Many virologists have
predicted for some years that such an epidemic could strike again.
- More people are thought to have died of that flu in
a single year than in four-years of the Black Death Bubonic
Plague
from 1347 to 1351. Known as "Spanish Flu" or "La
Grippe" the influenza of 1918-1919 was a global disaster.
- Of course today we were helped a great deal by global
media, good facilities for tracking and acted fast. That's
why
some
dismissed the
comparison. But we also have global air travel, the world
population is far more urbanised and larger, and huge parts
of the world
are still very underdeveloped. As I said at the time, such
a scenario was unlikely but it was a possibility which
is why the World
Health Organisation was right to stress the need for urgent
global action.
EXTENT OF THE SARS NIGHTMARE - What we
learnt - history
- A single new case can set off a major outbreak in any
town or city, particularly if diagnosis is delayed. SARS
can spread faster in intitial stages than local teams can respond
as we've seen in
Toronto Canada, where over 7,000 were in strict isolation by
April 2003, despite one of the best health systems in the world
- all resulting from a single SARS infection some
weeks earlier.
- While most people with SARS do not seem to infect significant
numbers of others (or none at all), a small minority appear to
be highly infectious, and may be the origin of many new outbreaks
we have been seeing.
HISTORY OF SARS - REASONS FOR CONCERN
- The first case of SARS infection was reported in Hanoi on 26
February: a man was admitted to hospital with symptoms of high
fever, dry cough, myalgia (muscle soreness) and sore throat. Over
the next four days he developed increasing breathing difficulties,
severe thrombocytopenia (low platelet count which means his blood
was not able to clot properly) and severe breathing difficulties
requiring ventilator support. He died of SARS pneumonia. Today
we know the truth which is
that SARS infection has been around for months, hidden away in
China.
- By early April 2003, many countries were already deeply alarmed
by cases in their hospitals of a highly infectious viral infection
causing severe atypical pneumonia, striking suddenly, failing
to respond to normal treatment and causing many sick people to
die. The streets of Hong Kong were filled with people wearing
surgical masks, or holding pieces of cotton over their faces
- Evidence was growing in both Hong Kong and mainland China
that suggested SARS virus not only spreads via face to face
contact,
or to people nearby, but also can jump rapidly from person to
person, home to home in other ways - probably through contaminated
objects being touched by hands which then touch the nose, or
possibly through common sewage or water supplies.
The virus has been detected not only in respiratory droplets
but
also in faeces and urine. The virus remains infectious
in both faeces and urine for at least 24-48 hours - up to 4 days
in diarrhoea.
- Singapore closed all schools and threatened huge fines on anyone
in contact with an SARS sufferer if they left their homes.
- A day later Hong Kong also told a million students and children
to stay at home, with new SARS outbreak rates running at around
65-80 a day. And almost all of these people needed urgent hospital
admission, many in intensive care on life-support systems with
full-blown SARS pneumonia.
- The US had seen 37 cases of SARS infection by mid April with
numbers rising rapidly. Almost all had become infected in other
nations. Urgent steps were being taken to repatriate foreign office
staff from embassies and government consulates in Hong Kong,
and Guangzhou.
HONG KONG ALARM AT UNUSUAL SARS SPREAD IN
TOWER BLOCKS
- Hong Kong took action to effectively imprison 230 people in
an entire 35 story high-rise block of flats for 10 days, where
there had been over 100 SARS cases - almost half identified in
48 hours. However no action was taken to contain residents of
3 other towers among the 19 in the area, where a further 120 cases
had occurred. All cases were traced back to four initial visits by someone with a kidney problem who entered one of the
tower blocks after being treated in a hospital where
many people had pneumonia.
- The SARS virus seemed to have moved rapidly from one household
to another, up and down floors in these tall towers. World Health
Organisation experts were shocked when they realised that the
virus could hit people who had never even been in the same room
as someone already infected. These residents became dependent
on deliveries of food and other supplies by government employees.
However, when police officers in masks turned up to seal the
building, they discovered that half the residents
had fled. Frantic efforts followed to try and track down every
missing person across the whole of Hong Kong - among a population
of over 6 million. The military then decided to truck over 200
people to an isolated quarantine camp.
- Hong Kong health care teams were overwhelmed by the huge jump
in cases, making it impossible to work out who infected
who, how and in what order. Yet this kind of information is vitally
important in understanding how the virus spreads, and what kind
of isolation
measures are ecessary.
- Contact tracing, follow up and strict isolation of all potentially
exposed is very labour intensive and a highly specialist area.
It is the only weapon we have currently against the SARS epidemic,
but rapid spread in Hong Kong is making the job very difficult
for a small number of infectious disease experts - even more
so in China.
GLOBAL IMPACT WIDENS OF SARS INFECTION
- Investor confidence was hit across the region, together
with tourism and business travel. Intel Corp shut part of its
Hong Kong office and sent a third of its 250 Hong Kong workforce
home after a team member became sick with SARS pneumonia. HSBC
opened its backup trading floor at a different location in case
its entire top trading team was suddenly placed in quarantine.
Airline routes were threatened by mass cancellations.
- Other nations were also proposing radical action to save lives
and their health care systems from meltdown. A single SARS infection
was enough to close an entire hospital - with rapid spread to
health care workers and threats to other sick patients and family
members.
- Measures in the US, Canada, Australia, Singapore and other nations
allowed authorities to quarantine people against their will if
thought to be at risk.
- Many countries began delivering dire health warnings to travelers
- for example Australia told citizens to avoid all travel to Canada
and affected countries in the Far East.
- Travelers in Japan, China and Hong Kong began to see large
numbers of local citizens covering their faces in public places
with medical masks or make-shift pieces of cotton.
- Ontario, Canada declared a provincial SARS emergency allowing
legal action to remove personal freedoms for those affected if
necessary to prevent spread (compulsory quarantine). Ontario has
a resident Chinese population of over 400,000 with frequent travelers
to and from the Chinese mainland.
- Taiwan decreed SARS an "infectious disease" subject
to quarantine laws and banned visits by civil servants to affected
areas, including mainland China, Hong Kong and Vietnam. Over 500
were in strict SARS quarantine by the end of March and the government
announced they were thinking of a ban on air travel to or from
China. Taiwan media has savagely attacked Chinese leadership for
what they say has been slow action, risking the health of the
whole world by being secretive. Hong Kong authorities have also
been criticized for slowness to act - perhaps out of deference
to the authorities in China.
- The World Health Organisation also blamed China for being
slow to tell the world what was going on - and China also apologized
profusely for being inefficient in communicating the situation.
- WHO teams declared that despite great efforts to contain SARS
spread in Guandong, where facilities were good, there was grave risk of uncontrolled spread into more rural areas or other cities
with less strongly developed health care systems (including Beijing).
Rumours in early April suggested the true number of Beijing SARS
cases could be double those reported.
- On 15 April WHO discovered that SARS cases in military
hospitals were not being included in China statistics, a serious
omission that increased official figures in Bejing
alone from 37 to almost 400 actual cases with hundreds more
suspect cases, and many thousands more at risk from recent contact. To make
matters worse, suspect SARS cases were being nursed next to
confirmed cases, and SARS infections were being reported across
many other parts of rural China where facilities for monitoring,
contact tracing, isolation and treatment were, according to WHO,
likely to be poor.
- The scale of global mobility is breathtaking - with over
750,000 visitors from India to the UK each year for
example. Containment becomes even more difficult when you
consider that passengers could in theory be infected in-flight
from a passenger who disembarks before they even board the plane
-
just
by touching a food tray, or a light switch contaminated the day
before.
MEDICAL TEAMS HIT HARD BY SARS VIRUS
- Medical teams have been badly affected by SARS pneumonia. In
Hong Kong Chief the Medical Officer described his horror as seeing
over
60 doctors and nurses struck down with SARS symptoms of fever,
cough and atypical pneumonia, decimating the ability of his hospitals
to cope, and creating terrible fear - from a single person with
SARS.
- Some of these health workers
then unknowingly infected their own children, husbands, wives
and friends.
- 8% of all medical staff at the Hong Kong Prince of
Wales hospital fell sick with SARS in two weeks, with suggestions
in local press that a significant number may have been infected
despite infection control measures being taken. It is not clear
whether some / all had just been using masks or whether they had
been following the strict disciplines of full isolation and barrier
nursing, which does seem to be very effective - see below. Doctors
in clinics have been infected as well as family doctors (General
Practitioners) working in the community.
- The Italian doctor who identified the SARS virus himself died:
Dr Carlo Urbani, a 46-year-old Italian and expert on infectious
diseases, identified Severe Acute Respiratory Syndrome in an American
businessman admitted to hospital in Vietnam in February with severe
atypical pneunonia.
- Health care workers were still becoming ill with SARS from
new infections in early May, despite all the guidelines from
the World Health Organisation on infection control. Experience
shows that protecting health care workers while delivering care
to those with SARS is a major challenge.
- Symptoms of SARS, which is believed to be spread mainly through
droplets by sneezing and coughing, are hard to diagnose as SARS
infection
because they include common health problems as high fever, chills,
coughing, cold, headache, aches and pains, and breathing difficulties
of various kinds - read
on for more below on SARS symptom profile.
- An average of 10 in every 100 who are infected go on to die
of SARS, usually 5-6 weeks after becoming ill.
- Many people are recovering from SARS pneumonia, but often only
slowly, after long treatment in hospital, including the need
for support from mechanical respirators (life support systems
/ ventilators)
in intensive care units. The demands on health care resources
from a single case are immense. SARS infection produces a spectrum
of very severe illness and longer term effects on health are
unknown. A very small minority relapse with SARS a second time
after appearing to recover fully.
- Hong Kong has had 200 people with SARS in intensive care, creating
severe strains on health care resources, especially when intensive
care workers themselves have been struck down. Four doctors and
nurses became infected trying to resuscitate just one patient.
- Several entire hospitals have been cleared for SARS in Beijing
and a 1,000 bed new hospital built in 7 days, with 1,000 separate
rooms on the ground floor, each opening directly to the grounds
of the hospital.
ORIGINS OF SARS VIRUS
- Because the SARS epidemic suddenly seemed to appear from nowhere
just as the Iraq war began, some feared SARS infection was a biological
warfare attack - a germ warfare virus released by Saddam. We know
this is not the case since the spread of SARS began months earlier.
However scientists do have the technology to produce viruses like
SARS - see video on biological
warfare and feature on
biological weapons / news of disturbing experiments using common
cold virus.
- Investigations by Hong Kong authorities suggest SARS infection
was brought into that territory in February 2003 by a semi-retired
professor of medicine from Guangdong Province. Three cases of
strange "atypical" pneumonia reported in November 2002
point to the Foshan area of Guangdong as the likely geographic
origin of the SARS virus. Other SARS cases followed but there
were no reports permitted in the Chinese press, despite (as we
later learned officially) growing numbers of deaths. By late March
the Guangong Province admitted they had seen almost 800 SARS cases
with 34 deaths.
- The Chinese government only disclosed official figures of infections
and deaths at the end of March, after deaths were reported throughout
the world caused by a rapidly spreading atypical viral pneumonia,
all trailing back it seemed into China. This crucial delay has
meant that China itself is now likely to face a far more severe
SARS epidemic, and made spread much more likely elsewhere. The
SARS epidemic is acutely embarrassing to all countries with cases
on their own soil, and particularly to the Chinese who are deeply
sensitive to losing face, appearing weak or blameworthy to the
rest of the world.
- By the end of March WHO officials were working their way through
patient records in Beijing where there were also growing numbers
of cases, but had still not been permitted to make their first
visit to Southern China which it is thought to be the global epicentre
of the SARS epidemic, raising growing concerns about the real
nature of the problem in Guangdong. Health care workers in the
area had been forbidden to talk about what is happening. Stories
are circulating in Taiwan that local journalists have also been
instructed not to report what they are seeing.
- Judging by the experience of Hong Kong, and the slow reluctance
of the Chinese authorities to allow observers into Guangdong,
it was becoming hard to believe that the Chinese epidemic had
been fully contained. Control depends on full co-operation by
the whole population, reporting symptoms early, taking sensible
precautions. But how can you control disease like SARS during
an information blackout with strict censorship?
- The Chinese government sacked the health minister and
the major of Beijing but the damage was done, with
accelerated spread and loss of confidence in government by the
population.
- China faced a national crisis with thousands fleeing cities
like Beijing, possibly carrying infection with them across many
SARS-free areas. Normal life in some places ceased. After
much delay the government went to the other extreme,
with draconian measures including quarantine
for entire buildings, thousands of workers, entire hospitals,
severe
limitations
on
travel, cancellation of public holidays, huge fines for spreading
false rumours and so on.
SARS BACKGROUND - WHY WE ARE VULNERABLE
TO MUTANT VIRUSES
- Since 1987 I have been predicting the great vulnerability of
our world to new mutant viruses or mutations of existing ones,
in my book The
Truth about AIDS, and again in Futurewise published
in 1998 ( now in a third edition). The SARS virus currently
causing such global concerns is just one
of a
large
number of
totally
new agents emerging each year, the vast majority of which are
relatively harmless causing combinations of aches, pains, fevers,
rashes, gut problems and other symptoms. Twenty years ago medical
students were trained to diagnose virus infections by their typical
symptoms and skin rashes, but today the range of low-grade viral
infections is huge and rapidly growing. Few are formally diagnosed.
Doctors just tell people they are suffering from a "self-limiting
condition" which is another way of saying there's no treatment
but it is unlikely to kill you. But that was before SARS.
- Southern China is a place where new viruses often emerge, sometimes
jumping from animals to humans. Viruses have the capacity to
recombine
with new genetic material as they spread. Most viruses are species-specific
but occasionally they cross over. We saw this in 1998 with a
severe outbreak of bird flu in Hong Kong which killed several
people and only halted after over 1.3 million chickens were
slaughtered.
We have seen it again in April 2003 in the Netherlands with a
further outbreak affecting humans and the slaughter of over a
million chickens there. Fortunately the virus does not seem to
be able
to spead
very well between
humans.
- Last year we saw a new virus emerge called H5, also in Hong
Kong. It killed 50% of those infected but fortunately proved difficult
to catch. However, another of these recent mutant viruses is of
course HIV, which already
has spread to 1% of the entire world's 15-55 year olds, with
almost 100% death rates from AIDS. Another, a hundred years ago,
killed 30 million people - see below.
- Most new viruses are either harmless or relatively uninfectious,
or both. HIV is an example of a dangerous virus that is far
harder to catch that SARS virus, yet a global menace because people can live for many
years in an infectious state without realising they are a potential
risk to others..
- With 6 billion people alive today, a small risk of viral mutation
every time a single person is infected with any existing viral
type, dense urbanisation in many countries, dramatic growth in
international travel, and the lack of an antiviral equivalent
to penicillin, conditions have been perfectly set for some time
for just such outbreaks as SARS. We should therefore expect more
to follow - less or more dangerous than SAR.
- All this underlines the urgent need to develop effective antiviral
medication. It is shocking that 60 years after the discovery of
penicillin we still do not have a single antiviral that is as
effective as the earliest antibiotics. When we do, we will have
a cure for common cold, flu, polio, smallpox, viral meningitis
and viral pneumonia - amongst many other conditions. Genetic
engineering may be a key weapon in vaccine development.
SARS SYMPTOMS, INCUBATION PERIOD, INFECTIVITY,
TRANSMISSION, TREATMENT AND PREVENTION
- SARS stands for Severe Acute Respiratory Syndrome.
- SARS symptoms start with a fever of more than 38.5 centgigrade
or 100.4 degrees F, sometimes with shaking, headache, muscular
stiffness, body aches, confusion, rash, diarrhoea, loss of appetite
and malaise (feeling generally unwell). Within a short period,
the patient
develops a dry cough, and in many cases shortness of breath.
- On average it takes 3-5 days from first symptoms to someone
seeking hospital treatment. In 10% to 20% of cases, patients
require mechanical ventilation to
breathe. Symptoms of SARS
start in most cases 2 to 5 days after exposure but sometimes
it seems to take as long as 10 days - rarely up to 2
weeks.
- At first WHO said only 4% with SARS died, then 5%. Latest
analysis of data from Hong Kong suggests the rate is probably
around 10% on average. A key factor is age. Death rates are up
to 50% in those who are over 65 even if treated early. Fatalities
can
be as low as 4% in those in their 20s - but even this is very
high compared to most other infectious diseases today.
- Up until recently most deaths were in the elderly or those who
were unwell from other causes, but recent deaths have included
women in their 30s, while babies have become ill after women
with SARS have given birth. Some fear the virus is
becoming more virulent.
- People in early stages of incubation without symptoms do not
seem to be infectious.
- Some people have been in very close proximity to those with
SARS without becoming infected - infectivity can vary greatly
from person to person.
- Prompt medical care with supportive treatment seems to reduce
fatalities significantly.
- SARS diagnosis is by exclusion: there is no specific reliable test at
present which can be used in the early stages of infection.
Physicians and health care teams work hard in every suspected
case to rule out every other known cause of severe pneumonia.
And then as a last resort they conclude this must be SARS. In
the meantime, all with severe pneumonia anywhere in the world
who have been potentially exposed must be regarded as possibly
suffering from SARS until otherwise proven. That is why many with
symptoms similar to SARS are at present often included for a while
in SARS statistics, later being eliminated from the infection
list as the real cause becomes clear.
- As infection continues,
levels of specific antibodies always rise as the body starts to
fight, and blood tests can then reveal the causative organism.
However it takes 20 days of infection for the Elisa test to detect
antibodies accurately The immunofluorescence assay (IFA), detects
antibodies reliably as of day 10 of infection, but is a comparatively
slow test that requires the growth of virus in cell culture. The
PCR test for virus genetic material in theory could detect infection
very early but is presently still innacurate for SARS. The
German biotechnology company Artus claims it has developed a
test for SARS virus which gives accurate results two days after
infection. However the fact is that at present, many can carry SARS infection without realising
anything is wrong.
- Cause of SARS has been thought to be a coronavirus, the same
group as those causing common cold. However the virus has not
been found in 40%
of those in Canada with SARS infection, yet occurs in some who
are perfectly healthy. The reason may be that the virus
is already mutating again. if so this is a significant sign
of instability. If the SARS virus really has changed after
no more than a couple of thousand cases, then vaccine development
could be very difficult or impossible with current technology.
- Coronaviruses are notorious for changing their outer surface
antigens rapidly in subtle ways to confuse the immune system.
We call this process antigenic drift. That's why vaccines don't
work against colds.
- Of course until this basic issue is
resolved we can't even develop a testing system, let alone
a vaccine (See book chapter on
what exactly is a virus? which explains why viruses are
such a problem for human beings).
- Other factors may be at work. In some parts of China, chlamydia bacteria have
been found in the lungs of people with SARS - not found elsewhere.
Chlamydia infection is a well known STD (Sexually Transmitted
Disease) associated with pelvic inflammatory disease in women.
- SARS virus spreads mainly occurs through droplets created
by coughing or sneezing, but also spreads far less efficiently
through hand to nose
contact, if hands become contaminated with virus - for example
through picking up or touching an object such as a pen, or an
elevator button, and then touching the nose. It may also spread
through other routes - for example through faecal contamination
or sewage - we don't yet know.
- We have no idea how long the SARS
virus can survive on contaminated objects (called formites) but
latest research shows that the virus can remain infectious
outside the body for several days depending on the environment.
Surface contamination remains active for up to 24 hours, urine
and faeces remain
infectious for at least 1-2 days, while the virus survives
in diarrhoea for up to 4 days.
- We also have little idea how soon
carriers become infectious, or
if someone can be infectious without significant symptoms (silent
carrier). It is likely that we will find that a small minority
of people with genetic resistance will shake off SARS infection
without becoming very ill or being diagnosed, creating further
problems with tracking spread.
- If the virus becomes less virulent it could be harder to track
and control. The sudden onset of tyical severe symptoms of SARS
are helpful in making a rapid diagnosis. If many cases in future
are far
milder,
it
becomes more likely that they will escape labelling as SARS,
and spread may be harder to prevent.
- We assume at present that people
can become an infection risk 24-48
hours
before they
feel
ill.
- Hand-nose contamination is a very common way
cold viruses spread - and the answer is frequent hand washing as
well as avoiding hand - nose contact. Surfaces can be sterilised
with diluted bleach or disinfectants.
- Sales of face masks have soared in Hong Kong and elsewhere,
although there is little direct evidence that they will protect
the health of the wearer when walking around outside. They may
prevent infected droplets released by coughing or sneezing from
landing on the skin around the nose or from being inhaled, however,
individual virus particles are far too small to be filtered by
such masks. It all depends whether free virus particules are causing
infection, or far larger droplets of secretions which contain
virus.
- Those in recent contact with people who have SARS, or with
others who could be incubating SARS infection (themselves SARS
contacts
in the last 10 days to 2 weeks), should quarantine themselves,
keeping at home, away from others, in a well ventilated room,
eating
and
drinking a normal diet and getting plenty of rest. Urgent medical
advice should be sought, whether the person feels sick or well,
about detailed procedures to be followed to protect the health
of others while also enabling the person in quarantine to be
properly
looked after.
- 213 people appear to have been infected by SARS in one apartment
complex alone in Hong Kong - all of which landed up in hospital
- with a further 240 people from the same block in strict quarantine.
The question is how and why did they all become infected? Of the
213, over 100 were in a single residential block. The greatest
risk of transmission seems to have been to those living directly
above or below others already infected, suggesting a new factor
is involved other than normal person to person spread, such as
infected body secretions entering common ventilation or plumbing
systems of other flats. Huge efforts are being made to answer
this question. The Amoy Garden complex is in the Kowloon district
and has many 35 story residential blocks, housing a total of 15,000
people.
- The vital question is this: how close do you have to be to someone
with SARS virus infection, and for how long, in order to be at
significant risk of SARS? We don't know, just as we know very
little about the level of exposure required in normal day to day
situations to catch flu or a common cold. In China a man suffering
from an early case of SARS did not infect any of his own family,
despite being in close proximity, yet others outside the home
were infected. So there are many puzzles to be solved.
- Most experts believe that SARS virus is caught mainly by inhaling
an aerosol spray of fine particles comprised of body secretions,
released through someone nearby coughing or sneezing. Such aerosols
tend to fall to the ground and so, it is hoped, long distance
airbourne spread is highly unlikely - for example through an
air conditioning system in hotels, apartments or aircraft. Huge
efforts
are being made to work out how every person with SARS became
infected: from whom and in what way but the situation is still
very unclear. There has certainly been no evidence of true airbourne
spread so far.
- Some people with SARS are much more infectious than others
for reasons we don't understand - superspreaders. For example
one
person infected 56
health care workers in a Vietnam hospital. Some treatments
seem to be very dangerous to those around -for example using
nebulisers to create an inhaled mist. The mist can fill
the room with billions of infectious water microparticles.
- Barrier nursing using gloves, masks, gowns, aprons, head covers
and goggles seems to provide good SARS protection for nurses,
doctors and other health care workers - but it is not 100%. Barrier
nursing is a standard procedure for many conditions and most
hospitals in the world
should be able to protect most of their health care workers from
occupational SARS infection this way. Ideally rooms (containing
of course only
one person or only others proven to have SARS already) should
be well ventilated with negative pressure systems so that air
is drawn into the room as the door is opened, and stale air is
constantly expelled outside the building.
- Every object inside the room must be regarded as an infectious
hazard including eating utensils, plates, medical records, windows,
door handles,
ventilators and all other medical equipment.
- SARS has been called flumonia because it spreads like flu and
kills like pneumonia.
- SARS deaths occur when lung tissue swells so that breathing
becomes impossible - something that can occur in perhaps more
than 10% of the elderly and less than 5% of the young.
- SARS experimental treatments have included the use of high dose steroids
and antiviral medication using Ribavirin, with uncertain
results.
- SARS recovery rates seem to be higher in the young and those
without other illnesses. In a mixed population 85% with SARS
pneumonia
recover within a week of becoming sick, perhaps 5% are ill for
far longer and it is thought that around 10% die - but these
are early days, and figures are
changing.
There is also the possibility that we may see various strains
of SARS virus with different mortality rates.
- SARS is probably a spontaneous viral mutation from other viruses
infecting animals and humans, a process called recombination.
- In countries like Singapore there has been a rush to sign up
for health insurance but people may be disappointed. Health insurance
cover may exclude SARS in countries where SARS has become a notifiable
infectious disease - check the terms of your policy.
THE POTENTIAL FOR CATASTROPHE IF ACTION
FAILS NOW
- So then, SARS had the potential to produce a global pandemic
unless radical action was taken by governments.
- A single SARS-virus infected individual can spark a fresh outbreak,
and since some people can be highly infectious before the diagnosis
is
obvious, and since the early symptoms (cough and fever) are similar
to many other conditions, it can be hard to track spread.
- We also know that a small number who seem to have recovered
can later relapse, becoming infectious and unwell all over again.
- Global travel has never made it harder to stop spread of illnesses
such as colds and flu - which appear to spread like SARS. So
SARS
has the potential to spread far faster and wider than the 1918-1919
flu epidemic.
- Set against that we have a far better understanding of the
disease than was the case with Spanish flu, far better monitoring
and surveillance and greater global awareness.
- We have seen that containing SARS means tight control, and
most importantly excellent national communication, with well
understood
health
campaigns
so that the whole population is mobilised rapidly. This may be
particularly difficult in remoter parts of
China or
India or Africa.
- If a significant future SARS outbreak hits a densely populated
city like Calcutta or Bombay and the rural areas beyond, (these
cities
already have cases) it will be very
difficult
to contain
with a highly mobile
population of over a billion people, huge overcrowding, ignorance
of the disease, difficulty in diagnosis, poorly developed health
infrastructure, low access to radio and TV, high levels of illiteracy
among the poor and the impossibility of quarantining many tens
of thousands of people. Only those who have traveled to India
or live there
can fully understand the vast scale of the challenge
if India should see an established outbreak on its own soil.
THE FUTURE OF SARS EPIDEMIC
- What should we expect of SARS in the future? Hopefully the
virushas been contained or has mutated
into a less virulent form - as happened with the 1918-1919
Spanish flu. Aggressive public health measures seem to have succeeded
in preventing SARS from spreading into populations where there
are
few public health
resources. We will soon have much more data on the virus, and
the ability to collect serum from those who have recovered that
may help save lives. We may be able to develop a vaccine quite
rapidly - by injecting people with damaged virus particles, or
by finding a variant which produces very mild illness, but is
similar enough to provoke protective antibody responses. But
that will only be possible by bypassing normal strict safety
testing.
- A key challenge with SARS is the fear governments have of spreading
panic, not only among their own people, but also among tourists
and investors. However, the epidemic has had the potential to
become a real threat to global health and if allowed to spread
much
further,
could have become a wild-fire impossible to put out.
- Conclusion: the World Health Organisation
was correct to take this SARS epidemic very seriously indeed.
Outcome
will still depend on global efforts by every government and
every health agency, working together.
|
|
WHO SARS STATISTICS ON 16 APRIL 2003
| Country |
Cumulative
number of case(s) |
Number
of new cases since last WHO update |
Final Status
|
Local chain(s) of
transmission
|
| Number of
deaths |
Number
recovered3 |
| Brazil |
2 |
0 |
0 |
0 |
None
|
| Canada |
103 |
3 |
13 |
37 |
Yes |
| China |
1432 |
14 |
64 |
1094 |
Yes |
| China, Hong Kong Special
Administrative Region 5 |
1268 |
36 |
61 |
257 |
Yes |
| China, Taiwan |
27 |
4 |
0 |
10 |
Yes |
| France |
5 |
0 |
0 |
1 |
None |
| Germany |
6 |
0 |
0 |
4 |
None |
| Indonesia |
1 |
0 |
0 |
0 |
None |
| Italy |
3 |
0 |
0 |
2 |
None |
| Japan |
1 |
0 |
0 |
0 |
None |
| Kuwait |
1 |
0 |
0 |
0 |
None |
| Malaysia |
5 |
1 |
1 |
0 |
None |
| Philippines |
1 |
0 |
0 |
1 |
None |
| Republic of Ireland |
1 |
0 |
0 |
1 |
None |
| Romania |
1 |
0 |
0 |
1 |
None |
| Singapore |
162 |
0 |
13 |
85 |
Yes |
| South Africa |
1 |
0 |
0 |
0 |
None |
| Spain |
1 |
0 |
0 |
0 |
None |
| Sweden |
1 |
0 |
0 |
0 |
None |
| Switzerland |
1 |
0 |
0 |
1 |
None |
| Thailand |
8 |
0 |
2 |
5 |
None |
| United Kingdom |
6 |
0 |
0 |
3 |
Yes |
| United States |
193 |
0 |
0 |
not
available |
Yes |
| Viet Nam |
63 |
0 |
5 |
46 |
Yes |
| Total |
3293 |
58 |
159 |
1548 |
|
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Dr Patrick Dixon is a physician
with experience in HIV / AIDS and has been tracking the dangers
of lethal virus infections for over 15 years. Sources for this commentary
include The World Health Organisation and media reports around the
world, as well as a visit in March 2003 to China / Hong Kong.
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